Horizontal slat-type, roll-up blinds, are conventionally formed of numerous, substantially identical, elongated slats which are arranged one above another and which are hingedly connected together along their adjacent edges. In this type of blind, the upper, elongated edges of each slat may be provided with an elongated flange which is bent into a downwardly opening hook. The lower ends of each of the slats are formed as channels with one wall of each channel being bent upwardly to form an upwardly opening hook. Thus, the hook flange of the upper edge of one slat is engaged within the channel in engagement with the hook formation of the channel.
With this type of construction, the slats are hingedly connected together and may be rolled up or down as desired. However, in this type of flange, there is a problem in maintaining the alignment of the slats relative to each other. That is, the slats tend to shift sideways during periods of use and therefor, a mechanism is needed to maintain the alignment of the slats.
Various types of devices have been used to try to maintain the alignment of the slats, such as brackets, fittings, etc. However, the conventional techniques for maintaining the alignments of the slats is relatively ineffective and somewhat expensive.
Thus, it would be desirable to provide some simplified way of maintaining the inter-connected slats in alignment by using the slates themselves without additional fasteners or brackets or the like in order to simplify the construction and reduce the costs. This invention relates to such a system for interlocking the slats in such a way that they do not shift sideways relative to each other.